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. 6, 1932. e. P. LUCKEY Q SENSITIVE ALTIMETER Original Filed June 27, 1923 INVENTORQ manna/0(5).-

A TTORWEYv Reissued Dec. 6, 1932 treme sensitivity a UNITEDOSTIATES PATENT OFFICE GEORGE P. LUCKEY, OF LANCASTER, IPENNSYLVANIA, A SSIGNOR TO PIONEER INSTRU- MEN'I COMPANY, INCORPORATED, OF BROOKLYN, NEW YORK, A CORPORATION OF NEW YORK SENSITIVE ALTIMETER Original No. 1,749,494, dated March 4, 1930, Serial No.

filed March 16, 1931.

This invention relates to altimeters and has particular reference to an altimeter of em and range for aeronautical use. j

It is the prime object of this invention to provide an altimeter that will be rugged,

compact, accurate and sensitive to the smallest change in altitude and which will be accurate over a great range of variation in altitude. I

It is the further object to provide an instrument of this character, with a temperature compensating device which may be easily adjusted so as to simultaneously vary the effective length of a lever arm in two ,series of transmitting systems connected to two separate aneroid capsules.

Further objects will be more fully set forth in'the attached specification and claims.

In the drawing Fig. 1 is a sectional elevation of an embodiment of my invention. I

Fig.2 is a top plan View, and Fig. 3 is a detail of the link connections between the aneroid capsules.

Referring to the drawing, 2 is a bowlshaped housing having a glass or other transparent top 4 and carrying the operating mechanism including dials 6 and 8 with zero adjusting mechanism 10 for the former. The zero adjusting mechanism includes a pinion 10a carried by a shaft 106 and meshing with a gear portion 100 secured to the dial 6 for causing relative movement between said dial and the pointers. In order that relative movement may be had between the dials 6 and 8 and/or between dials 6 and the indicators, the dial 8 may be secured to the yoke example, as zero when the 16 in any well-known manner or to any other neoted ends of these arms 648,057, filed June 27, 1923. Application for reissue 'Serial No. 523,093.

same is a skeleton supporting disk 12 upon which two bellows or aneroid capsules 14 preferably of metal, are mounted, while supported from the disk 12 are yokes 16 and 18, upon which the levers, bearings and gear trains are mounted. To the inner ends of the capsules are rigidly secured in any suit able manner, projections 20, 22, pivoted to arcuate links 24 and 26 which in turn are pivotally connected with angularly adjustable arms 28, 30 guided by auxiliary arms 34 and 32, which are pivoted'together at 36 on a shaft 38. The shaft 38 is mounted in jewelled bearings and provides a support for a so that the desired number of revolutions of the hand 54 for one revolution of the hand 52 are obtained. The dials 6 and 8 are graduated in equal spaces, the first for example, being graduated for one thousand feet change in altitude per revolution, and the latter for any'desired multiple of the one thousand feet change.

Referring more particularly to Fig. 3, the links and arms connecting the projections 20 and 22 to the shaft 38, are especially designed to change the motion of the aneroid capsules for equal changes in pressure, in o a uniform circular motion by a proper pro ortion of the lengths of-the various arms and links, the distance between the aneroid conand the'pivot 36, the lateral spacing of the links 24 and 26, and the distance between the point 36 and the inner ends of the links 24 and 26. The nonuniform rectilincar motion of the capsules is changed into a uniform circular motion by this mechanism and the scales therefore con-' tain equal graduations. This is absolutely the pointer.

The ends of the links 24 and 26 are attached to the point 36 through an adjustable linkage 28, 34 and 30, 32. Calling the end of the link 24, a, the point 36, b, and the end of link 26, c, the distance ab is an lmaginary link connecting 24 to 36, the length of which may be varied manually, if desired, in order to adjust the range of movement of the pointer. aueroid capsules are used from those intendcd, or in case one is replaced in a finished instrument. By this means, also, it is possible to make the scales in quantities with the assurance that the instrument may be'easily adjusted to accommodate itself to this scale. The arms or links 28 and 30, are attached together and to an adjusting screw 56. 'By ad usting this screw 56, lever arms ab and be are simultaneously lengthened or shortened and to an equal degree. The projection 20 .is substantially aligned with a in its normal position and the straight line abc as shown,

is normally, at zero reading of the instrument, at such an angle to the line of motion of the projections 20 and 22 that decreasing lineal increments of motion of the projections 20 and 22 inward will produce equal arcuate increments of motion of the points a and 0 about axis 38. Since the total angular movement of the line abc is only about degrees,

' the proper location of the line abc in relation to the line of motion of the projections2Q and 22 may be chosen so that the shaft 38 is rotated through substanially equal angles as the pressure of the outside air varies'equal amounts, and as the bellows 14 expands in decreasing amounts which vary, like a spring, about as the square rootof the changes of air pressure. 7

In order that compensation may be made for temperature changes, two links such as the links 28 and 30, or the links 32 and 34, or the adjusting screw 56 of the toggle adjusting mechanism, may be made of the material or combination of materials of suitable coet'fi-' cients of thermal expansion. With such a construction the arms ab and be may be automatically varied in a suitable manner by a temperature change of the atmosphere or of the instrument and which will correct errors I introdu'ced'by the expansion of parts ofthe mechanism.

What I claim is:

1. Inan instrument having sealed atmospheric pressure responsive'means, a plurality of dials, an indicator for each of said dials, one of said indicators being geared to the other so as to move only a fraction of a revo- This may be necessary in case different of the said indicators in respect to the movement of said pressure responsive means.

2. In an instrument having atmospheric pressure responsive means, a large and a small dial, a large and a small indicator adapted to register over said dials respectively, gearing interconnecting said indicators so that said small indicator moves a fraction of a revolution for each complete revolution of the larger indicator, and a system of pivotally connected links connecting said indicators to said pressure responsive means for transforming unequal movements of d pressure responsive means into uniform rotary movements of. said indicators.

3. In an altitude indicator in combination, a plurality of spaced atmospheric pressure responsive bellows, a dial, a pointer adapted to register over said dial, link means between each of said bellows and said pointer for transferring movements of said-bellows to said pointer, and a unitary adjusting means for sald llnk means to simultaneously and equally vary the ratio of the movement of each of said bellows to the movement of the pointer.

4. In an altimeter having pressur -responsive means, a plurality of point adapted to be actuated thereby, said pointers being so arranged relative to each other that each is actuated to a different extent, a pair of dials for indicating the degree of actuation of said pointers, means connecting said pressure-responsive means to said pointers for transforming unequal movements of the former into uniform movements of the latter, said connecting means includingadj ustable means for changing the ratio of the movements of said pressure-responsive means to the movements of said pointers, and means for caus- 1ng relative movement between one of the dials and the pointers for setting the altimeter so that a zero indication is obtained at a predetermined altitude.

5. In an instrument having pressure-responsive means adapted to be actuated lineally, a plurality of devices adapted 'to be rotatably actuated thereby, said devices being so arranged relative to each otherthat each is actuated to a different extent, means for indicating the degree of actuation of eachot said devices, and means connecting said pressure-responsive means to said devices for transforming unequal linear movements of the former into uniform rotaryimovements of each of the latter, said connecting means including adjustable means for changing the ratio of the movements of said pressure-reiii.

sponsive means to the movements of said devices.

6. In an altitude indicator having atmospheric pressure-responsive means adapted to be actuated along a straight line, a pair of dials, a pair of indicators adapted to register over said dials, respectively, rotary means interconnecting said indicators so that one moves a fraction of a revolution for each complete revolution of the other, and a systemof pivotally connected links connecting said Indicators to said'pressure-responsive means for transforming unequal linear movements of the latter into uniform rotary movements of each of the former.

7. In an altimeter having pressure-responsive means, a pair of dials, a pair'of'indicators adapted to register over said dials, respectively, gear means interconnecting said indicators so that one movesa fraction of a revolution for each complete revolution of the other, amplification mechanism connecting said gear means to said pressure-responsive means for transforming unequal movements of said pressure-responsive means into uniform rotary movements of each of said indicators, and adjusting means including a gear train and a knob operable from the front of the altimeter for causing'relative movement between one of said dials and said indicators so that said dial will indicate a zero reading at a predetermined altitude or barometric pressure.

8. In an altimeter having sealed atmospheric pressure-responsive means, a plurality of dials, an indicator for each of said dials, a gear train interconnecting said indicators for causing one of them to move only a fraction of a revolution for a complete revolution of the other, arock-shaft connected to said gear train and adapted to be actuated by the pressure-responsive means, link mechanism connecting said pressure-responsivemeans to said rock-shaft for transforming linear movements of said pressure-responsive means into rotary movements of each of said indicators, and adj listing means includin a gear train and a knob operable from the rout of the altimeter for causing relative movement between one of said dials and said indicators so that said dial will indicate a zero, reading at a predetermined altitude or barometric pressure.

9. In an altimeter having atmospheric pressure-responsive means, a pair of dials, an indicator for each of-said dials, a gear train interconnecting said indicators for causing one of them'to move only a fraction of a revolution for a complete revolution of the other, means connected to said gear train and adapted to be actuated by the pressure-responsive means for transforming linear movements of said pressure-responsive means into rotary movements of saidindicators, and adjusting means including a gear train and a knob operable from the front of the altimeter for actuating said last-mentioned gear train to cause relative movement between one of said dials and the indicators so that it will indi-- GEORGE P. LUCKEY. 

